Revolutionizing cancer monitoring with carbon-based electrochemical biosensors.

Cancer monitoring plays a critical role in improving patient outcomes by providing early detection, personalized treatment options, and treatment response tracking. Carbon-based electrochemical biosensors have emerged in recent years as a revolutionary technology with the potential to revolutionize cancer monitoring. These sensors are useful for clinical applications because of their high sensitivity, selectivity, rapid response, and compatibility with miniaturized equipment. This review paper gives an in-depth look at the latest developments and the possibilities of carbon-based electrochemical sensors in cancer surveillance. The essential principles of carbon-based electrochemical sensors are discussed, including their structure, operating mechanisms, and critical qualities that make them suited for cancer surveillance. Furthermore, we investigate their applicability in detecting specific cancer biomarkers, evaluating therapy responses, and detecting cancer recurrence early. Additionally, a comparison of carbon-based electrochemical sensor performance measures, including sensitivity, selectivity, accuracy, and limit of detection, is presented in contrast to existing monitoring methods and upcoming technologies. Finally, we discuss prospective tactics, future initiatives, and commercialization opportunities for improving the capabilities of these sensors and integrating them into normal clinical practice. The review highlights the potential impact of carbon-based electrochemical sensors on cancer diagnosis, treatment, and patient outcomes, as well as the importance of ongoing research, collaboration, and validation studies to fully realize their potential in revolutionizing cancer monitoring.

Calf thymus ds-DNA intercalation with pendimethalin herbicide at the surface of ZIF-8/Co/rGO/C3N4/ds-DNA/SPCE; A bio-sensing approach for pendimethalin quantification confirmed by molecular docking study.

Pendimethalin (PND) is a herbicide that is regarded to be possibly carcinogenic to humans and toxic to the environment. Herein, we fabricated a highly sensitive DNA biosensor based on ZIF-8/Co/rGO/C3N4 nanohybrid modification of a screen-printed carbon electrode (SPCE) to monitor PND in real samples. The layer-by-layer fabrication pathway was conducted to construct ZIF-8/Co/rGO/C3N4/ds-DNA/SPCE biosensor. The physicochemical characterization techniques confirmed the successful synthesis of ZIF-8/Co/rGO/C3N4 hybrid nanocomposite, as well as the appropriate modification of the SPCE surface. The utilization of ZIF-8/Co/rGO/C3N4 nanohybrid as a modifier was analyzed using. The electrochemical impedance spectroscopy results showed that the modified SPCE exhibited significantly lowered charge transfer resistance due to the enhancement of its electrical conductivity and facilitation of the transfer of charged particles. The proposed biosensor successfully quantified PND in a wide concentration range of 0.01-35 µM, with a limit of detection (LOD) value of 8.0 nM. The PND monitoring capability of the fabricated biosensor in real samples including rice, wheat, tap, and river water samples was verified with a recovery range of 98.2-105.6%. Moreover, to predict the interaction sites of PND herbicide with DNA, the molecular docking study was performed between the PND molecule and two sequence DNA fragments and confirmed the experimental findings. This research sets the stage for developing highly sensitive DNA biosensors that will be used to monitor and quantify toxic herbicides in real samples by fusing the advantages of nanohybrid structures with crucial knowledge from a molecular docking investigation.

Graphene oxide/cellulose nanofibril composite: A high-performance catalyst for the fabrication of an electrochemical sensor for quantification of p-nitrophenol, a hazardous water pollutant.

The detection and quantification of p-Nitrophenol in environmental samples are important for understanding the extent and impact of environmental pollution, protecting human health, ensuring regulatory compliance, and guiding remediation efforts. The main objective of this work was to investigate the electrochemical performance of a graphene oxide/cellulose nanofibril composite (GO/CNF) modified carbon paste electrode (GO/CNF/CPE) for the sensitive and reliable detection of p-nitrophenol in water samples. The transmission electron microscopy (TEM) technique was employed to enlighten the structure of nanocomposites. The electrochemical behavior of the fabricated electrochemical sensor was characterized via differential pulse voltammetry (DPV), linear sweep voltammetry (LSV), and electrochemical impedance spectroscopy (EIS). Under optimized analytical conditions, the peak current of the analyte showed a wide linear relationship with its concentration in a range of 3.0 nM-210 µM with a low amount of the limit of detection (LOD) value of 0.8 nM determined by the DPV method. The proposed electrochemical sensor demonstrated excellent sensitivity, selectivity, and accuracy metrics in real sample analysis of p-nitrophenol.

Modeling of adsorptive removal of azithromycin from aquatic media by CoFe2O4/NiO anchored microalgae-derived nitrogen-doped porous activated carbon adsorbent and colorimetric quantifying of azithromycin in pharmaceutical products.

Herein, it was aimed to optimize the removal process of Azithromycin (Azi) from the aquatic environment via CoFe2O4/NiO nanoparticles anchored onto the microalgae-derived nitrogen-doped porous activated carbon (N-PAC), besides developing a colorimetric method for the swift monitoring of Azi in pharmaceutical products. In this study, the Spirulina platensis (Sp) was used as a biomass resource for fabricating CoFe2O4/NiO@N-PAC adsorbent. The pores of N-PAC mainly entail mesoporous structures with a mean pore diameter of 21.546 nm and total cavity volume (Vtotal) of 0.033578 cm3. g-1. The adsorption studies offered that 98.5% of Azi in aqueous media could remove by CoFe2O4/NiO@N-PAC. For the cyclic stability analysis, the adsorbent was separated magnetically and assessed at the end of five adsorption-desorption cycles with a negligible decrease in adsorption. The kinetic modeling revealed that the adsorption of Azi onto the CoFe2O4/NiO@N-PAC was well-fitted to the second-order reaction kinetics, and the highest adsorption capacity was found as 2000 mg. g-1 at 25 °C based on the Langmuir adsorption isotherm model at 0.8 g. L-1 adsorbent concentration. The Freundlich isotherm model had the best agreement with the experimental data. Thermodynamic modeling indicated the spontaneous and exothermic nature of the adsorption process. Moreover, the effects of pH, temperature, and operating time were also optimized in the colorimetric Azi detection. The blue ion-pair complexes between Azi and Coomassie Brilliant Blue G-250 (CBBG-250) reagent followed Beer's law at wavelengths of 640 nm in the concentration range of 1.0 µM to 1.0 mM with a 0.94 µM limit of detection (LOD). In addition, the selectivity of Azi determination was verified in presence of various species. Furthermore, the applicability of CBBG-250 dye for quantifying Azi was evaluated in Azi capsules as real samples, which revealed the acceptable recovery percentage (98.72-101.27%). This work paves the way for engineering advanced nanomaterials for the removal and monitoring of Azi and assures the sustainability of environmental protection and public health.

Engineering and application of polysaccharides and proteins-based nanobiocatalysts in the recovery of toxic metals, phosphorous, and ammonia from wastewater: A review.

Global waste production is anticipated reach to 2.59 billion tons in 2030, thus accentuating issues of environmental pollution and health security. 37 % of waste is landfilled, 33 % is discharged or burned in open areas, and only 13.5 % is recycled, which makes waste management poorly efficient in the context of the circular economy. There is, therefore, a need for methods to recycle waste into valuable materials through the resource recovery process. Progress in the field of recycling is strongly dependent on the development of efficient, stable, and reusable yet inexpensive catalysts. In this case, growing attention has been paid to the development and application of nanobiocatalysts with promising features. The main purpose of this review paper is to: (i) introduce nanobiomaterials and describe their effective role in the preparation of functional nanobiocatalysts for the recourse recovery aims; (ii) provide production methods and the efficiency improvement of nanobaiocatalysts; (iii) give a comprehensive description of valued resource recovery for reducing toxic chemicals from the contaminated environment; (iv) describe various technologies for the valued resource recovery; (v) state the limitation of the valued resource recovery; (vi) and finally economic importance and current scenario of nanobiocatalysts strategies applicable for the resource recovery processes.

Algae extract delamination of molybdenum disulfide and surface modification with glycidyl methacrylate and polyaniline for the elimination of metal ions from wastewater.

A special type of two-dimensional (2D) material based conducting polymer was constructed by green synthesis and in-situ polymerization techniques. The 2D Molybdenum Disulfide (MoS2) were first synthesized with the combination of, ammonium tetrathiomolybdate dissolved in 20 mL algae extract under stirring. After stirring for about 2 h, and then finally sulfurization was initiated using sulfur powder in 20 mL of sulfuric solution and stirred for 8 h. The resulting black precipitates of MoS2 were collected by centrifugation at 5000 rpm. Moreover, the prepared MoS2 was functionalized with glycidyl methacrylate (GMA) and form the MoS2@PGMA. Further, the MoS2@PGMA is combined with polyaniline (PANI) to form conducting polymer grafted thin film nanosheets named MoS2@PGMA/PANI with a thickness in micrometer size through grafting method. The prepared materials were characterized by SEM, FTIR, XRD, XPS and EDX techniques. To check the performance of materials the adsorption study was performed. Moreover, the adsorption study toward Cu2+ and Cd2+ showed a tremendous results and the maximum adsorption was 307.7 mg/g and 214.7 mg/g respectively. In addition, the pseudo-first and second order models as well as the adsorption isotherm were investigated using the Langmuir and Freundlich model. The results were best fitted with the pseudo-second order and Langmuir models. The regeneration study was also conducted and MoS2@PGMA/PANI nanosheets can be easily recycled and restored after five successful recycling. The established methodology for preparing the 2D materials and conducting polymer based MoS2@PGMA/PANI nanosheets is expected to be applicable for other multiple applications.

State-of-art advances on removal, degradation and electrochemical monitoring of 4-aminophenol pollutants in real samples: A review.

p_Aminophenol, namely 4-aminophenol (4-AP), is an aromatic compound including hydroxyl and amino groups contiguous together on the benzene ring, which are suitable chemically reactive, amphoteric, and alleviating agents in nature. Amino phenols are appropriate precursors for synthesizing oxazoles and oxazines. However, since the toxicity of aniline and phenol can harm human and herbal organs, it is essential to improve a reliable technique for the determination of even a trace amount of amino phenols, as well as elimination or (bio)degradation/photodegradation of it to protect both the environment and people's health. For this purpose, various analytical methods have been suggested up till now, including spectrophotometry, liquid chromatography, spectrofluorometric and capillary electrophoresis, etc. However, some drawbacks such as the requirement of complex instruments, high costs, not being portable, slow response time, low sensitivity, etc. prevent them to be employed in a wide range and swift in-situ applications. In this regard, besides the efforts such as (bio)degradation/photodegradation or removal of 4-AP pollutants from real samples, electroanalytical techniques have become a promising alternative for monitoring them with high sensitivity. In this review, it was aimed to emphasize and summarize the recent advances, challenges, and opportunities for removal, degradation, and electrochemical sensing 4-AP in real samples. Electroanalytical monitoring of amino phenols was reviewed in detail and explored the various types of electrochemical sensors applied for detecting and monitoring in real samples. Furthermore, the various technique of removal and degradation of 4-AP in industrial and urban wastes were also deliberated. Moreover, deep criticism of multifunctional nanomaterials to be utilized as a catalyst, adsorbent/biosorbent, and electroactive material for the fabrication of electrochemical sensors was covered along with their unique properties. Future perspectives and conclusions were also criticized to pave the way for further studies in the field of application of up-and-coming nanostructures in environmental applications.

Photocatalytic degradation of remdesivir nucleotide pro-drug using [Cu(1-methylimidazole)4(SCN)2] nanocomplex synthesized by sonochemical process: Theoretical, hirshfeld surface analysis, degradation kinetic, and thermodynamic studies.

The first ultrasonic synthesis of [Cu(L)4(SCN)2] (L = 1-methylimidazole) nanocomplex was carried out under ultrasonic irradiation, and its photocatalytic performance for the degradation of remdesivir (RS) under sunlight irradiation was comprehensively investigated for the first time in this study. The physicochemical properties of the synthesized photocatalyst were examined by Fourier-transform infrared (FT-IR), field emission scanning electron microscopy (FE-SEM), diffuse reflectance spectroscopy (DRS), and thermogravimetric analysis (TGA) techniques. The band gap of the synthesized [Cu(L)4(SCN)2] nanocomplex was determined to be 2.60 eV by the diffuse reflectance spectroscopy method using Kubelka-Munk formula. The photocatalytic performance of nanocomplex was examined for the removal of remdesivir under sunlight from water for which the results indicated that an amount of 0.5 gL-1 of the [Cu(L)4(SCN)2] nanocomplex was sufficient to remove more than 96% remdesivir from its 2 mg L-1 concentration within 20 min, at pH = 6. The kinetic data showed that the photodegradation onto the [Cu(L)4(SCN)2] nanocomplex has a high correlation (0.98) with the pseudo-second-order kinetic model. The decrease in chemical oxygen demand (COD) (from 70.5 mg L-1 to 36.4 mg L-1) under optimal conditions clearly confirmed the mineralization of the RS drug. The values of ΔS° (-0.131 kJ mol-1 K-1) and ΔH° (-49.750 kJ mol-1) were negative, indicating that the adsorption process was spontaneous and more favorable in lower temperatures. Moreover, the RS structure in the open shell state and the high HOMO and LUMO gaps based on the M06/6-31 + G (d) level of theory may be a confirmation of this fact. In addition, the Hirshfeld surface analysis (HSA) of the crystal packing of the prepared complex was discussed in detail to evaluate the interactions between the crystal packings. The results of this study confirm that the [Cu(L)4(SCN)2] nanocomplex can be successfully used for the photodegradation of pharmaceutical contaminants.

Electrochemical monitoring of 4-chlorophenol as a water pollutant via carbon paste electrode amplified with Fe3O4 incorporated cellulose nanofibers (CNF).

A crucial problem that needs to be resolved is the sensitive and selective monitoring of chlorophenol compounds, especifically 4-chlorophenol (4-CP), one of the most frequently used organic industrial chemicals. In light of this, the goal of this study was to synthesize Fe3O4 incorporated cellulose nanofiber composite (Fe3O4/CNF) as an amplifier in the development of a modified carbon paste electrode (CPE) for 4-CP detection. Transmission electron microscopy (TEM) was used to evaluate the morphology of the synthesized nanocatalyst, while differential pulse voltammetry (DPV), electrochemical impedance spectroscopy (EIS), and linear sweep voltammetry (LSV) techniques were implemented to illuminate the electrochemical characteristics of the fabricated sensor. The ultimate electrochemical sensor (Fe3O4/CNF/CPE) was used as a potent electrochemical sensor for monitoring 4-CP in the concentration range of 1.0 nM-170 µM with a limit of detection value of 0.5 nM. As a result of optimization studies, 8.0 mg Fe3O4/CNF was found to be the ideal catalyst concentration, whereas pH = 6.0 was chosen as the ideal pH. The 4-CP's oxidation current was found to be over 1.67 times greater at ideal operating conditions than it was at the surface of bare CPE, and its oxidation potential decreased by about 120 mV. By using the standard addition procedure on samples of drinking water and wastewater, the suggested capability of Fe3O4/CNF/CPE to detect 4-CP was further investigated. The recovery range was found to be 98.52-103.66%. This study paves the way for the customization of advanced nanostructure for the application in electrochemical sensors resulting in beneficial environmental impact and enhancing human health.

Advances in technology and utilization of natural resources for achieving carbon neutrality and a sustainable solution to neutral environment.

The greatest environmental issue of the twenty-first century is climate change. Human-caused greenhouse gas emissions are increasing the frequency of extreme weather. Carbon dioxide (CO2) accounts for 80% of human greenhouse gas emissions. However, CO2 emissions and global temperature have risen steadily from pre-industrial times. Emissions data are crucial for most carbon emission policymaking and goal-setting. Sustainable and carbon-neutral sources must be used to create green energy and fossil-based alternatives to reduce our reliance on fossil fuels. Near-real-time monitoring of carbon emissions is a critical national concern and cutting-edge science. This review article provides an overview of the many carbon accounting systems that are now in use and are based on an annual time frame. The primary emphasis of the study is on the recently created carbon emission and eliminating sources and technology, as well as the current application trends for carbon neutrality. We also propose a framework for the most advanced naturally available carbon neutral accounting sources capable of being implemented on a large scale. Forming relevant data and procedures will help the "carbon neutrality" plan decision-making process. The formation of pertinent data and methodologies will give robust database support to the decision-making process for the "carbon neutrality" plan for the globe. In conclusion, this article offers some opinions, opportunities, challenges and future perspectives related to carbon neutrality and carbon emission monitoring and eliminating resources and technologies.

Review of functionalized nano porous membranes for desalination and water purification: MD simulations perspective.

Today, it is known that most of the water sources in the world are either drying out or contaminated. With the increasing population, the water demand is increasing drastically almost in every sector each year, which makes processes like water treatment and desalination one of the most critical environmental subjects of the future. Therefore, developing energy-efficient and faster methods are a must for the industry. Using functional groups on the membranes is known to be an effective way to develop shorter routes for water treatment. Accordingly, a review of nano-porous structures having functional groups used or designed for desalination and water treatment is presented in this study. A systematic scan has been conducted in the literature for the studies performed by molecular dynamics simulations. The selected studies have been classified according to membrane geometry, actuation mechanism, functionalized groups, and contaminant materials. Permeability, rejection rate, pressure, and temperature ranges are compiled for all of the studies examined. It has been observed that the pore size of a well-designed membrane should be small enough to reject contaminant molecules, atoms, or ions but wide enough to allow high water permeation. Adding functional groups to membranes is observed to affect the permeability and the rejection rate. In general, hydrophilic functional groups around the pores increase membrane permeability. In contrast, hydrophobic ones decrease the permeability. Besides affecting water permeation, the usage of charged functional groups mainly affects the rejection rate of ions and charged molecules.

Two dimensional (2D) materials and biomaterials for water desalination; structure, properties, and recent advances.

BACKGROUND: An efficient solution to the global freshwater dilemma is desalination. MXene, Molybdenum Disulfide (MoS2), Graphene Oxide, Hexagonal Boron Nitride, and Phosphorene are just a few examples of two-dimensional (2D) materials that have shown considerable promise in the development of 2D materials for water desalination. However, other promising materials for desalinating water are biomaterials. The benefits of bio-materials are their wide distribution, lack of toxicity, and superior capacity for water desalination. METHODS: For the rational use of water and the advancement of sustainable development, it is of the utmost importance to research 2D-dimensional materials and biomaterials that are effective for water desalination. The scientific community has concentrated on wastewater remediation using bio-derived materials, such as nanocellulose, chitosan, bio-char, bark, and activated charcoal generated from plant sources, among the various endeavors to enhance access to clean water. Moreover, the 2D-materials and biomaterials may have ushered in a new age in the production of desalination materials and created a promising future. RESULTS: The present review article focuses on and reviews the progress of 2D materials and biomaterials for water desalination. Their properties, surface, and structure, combined with water desalination applications, are highlighted. Further, the practicability and potential future directions of 2D materials and biomaterials are proposed. Thus, the current work provides information and discernments for developing novel 2D materials and biomaterials for wastewater desalination. Moreover, it aims to promote the contribution and advancement of materials for water desalination, fabrication, and industrial production.

MWCNT/Ruthenium hydroxide aerogel supercapacitor production and investigation of electrochemical performances.

In this study, the material obtained from the sonication of the double-walled carbon nanotube and ruthenium chloride was produced as an aerogel. Then, symmetrical supercapacitor devices were made using them, and their electrochemical properties were investigated. XRD and FTIR were used in the structural analysis of the aerogel, STEM in surface images, and elemental analyses in EDX. Electrochemical analysis was performed by galvanostat/potentiostat. From the cyclic voltammetry analysis, the highest specific capacitance for MWCNT/Ruthenium hydroxide aerogels was achieved as 423 F/g at 5 mV/s. On the other hand, the corresponding values calculated from the charge-discharge curves were found to be 420.3 F/g and 319.9 F/g at the current densities of 0.5 A/g and 10.0 A/g, respectively. The capacitance retention of as-synthesized aerogel was 96.38% at the end of the 5000 consecutive consecutive cyclic voltammetry cycles.

Recent advances in the analytical strategies of microbial biosensor for detection of pollutants.

Microbial biosensor which integrates different types of microorganisms, such as bacteria, microalgae, fungi, and virus have become suitable technologies to address limitations of conventional analytical methods. The main applications of biosensors include the detection of environmental pollutants, pathogenic bacteria and compounds related to illness, and food quality. Each type of microorganisms possesses advantages and disadvantages with different mechanisms to detect the analytes of interest. Furthermore, there is an increasing trend in genetic modifications for the development of microbial biosensors due to potential for high-throughput analysis and portability. Many review articles have discussed the applications of microbial biosensor, but many of them focusing only about bacterial-based biosensor although other microbes also possess many advantages. Additionally, reviews on the applications of all microbes as biosensor especially viral and microbial fuel cell biosensors are also still limited. Therefore, this review summarizes all the current applications of bacterial-, microalgal-, fungal-, viral-based biosensor in regard to environmental, food, and medical-related applications. The underlying mechanism of each microbes to detect the analytes are also discussed. Additionally, microbial fuel cell biosensors which have great potential in the future are also discussed. Although many advantageous microbial-based biosensors have been discovered, other areas such as forensic detection, early detection of bacteria or virus species that can lead to pandemics, and others still need further investigation. With that said, microbial-based biosensors have promising potential for vast applications where the biosensing performance of various microorganisms are presented in this review along with future perspectives to resolve problems related on microbial biosensors.

Electrochemical α-fetoprotein immunosensor based on Fe3O4NPs@covalent organic framework decorated gold nanoparticles and magnetic nanoparticles including SiO2@TiO2.

The early diagnosis of major diseases such as cancer is typically a major issue for humanity. Human α-fetoprotein (AFP) as a sialylated glycoprotein is of approximately 68 kD molecular weight and is considered to be a key biomarker, and an increase in its level indicates the presence of liver, testicular, or gastric cancer. In this study, an electrochemical AFP immunosensor based on Fe3O4NPs@covalent organic framework decorated gold nanoparticles (Fe3O4 NPs@COF/AuNPs) for the electrode platform and double-coated magnetic nanoparticles (MNPs) based on SiO2@TiO2 (MNPs@SiO2@TiO2) nanocomposites for the signal amplification was fabricated. The immobilization of anti-AFP capture antibody was successfully performed on Fe3O4 NPs@COF/AuNPs modified electrode surface by amino-gold affinity, while the conjugation of anti-AFP secondary antibody on MNPs@SiO2@TiO2 was achieved by the electrostatic/ionic interactions. Transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) analysis, cyclic voltammetry (CV), square wave voltammetry (SWV), and electrochemical impedance spectroscopy (EIS) techniques were used to characterize the nanostructures in terms of physical and electrochemical features. The limit of detection (LOD) was 3.30 fg mL-1. The findings revealed that the proposed electrochemical AFP immunosensor can be effectively used to diagnose cancer.

Fabrication of sensor based on polyvinyl alcohol functionalized tungsten oxide/reduced graphene oxide nanocomposite for electrochemical monitoring of 4-aminophenol.

4-aminophenol (4-AP) is one of the major environmental pollutants which is broadly exploited as drug intermediate in the pharmaceutical formulations. The extensive release of 4-AP in the environment without treatment has become a serious issue that has led several health effects on humans. This work describe the determination of 4-AP through a new chemically modified sensor based on polyvinyl alcohol functionalized tungsten oxide/reduced graphene oxide (PVA/WO3/rGO) nanocomposite. The fabricated nanocomposite was characterized through XRD and HR-TEM to confirm the crystalline structure with average size of 35.9 nm and 2D texture with ultra-fine sheets. The electrochemical characterization of fabricated sensor was carried out by electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) to ensure the charge transfer kinetics of modified sensor that revealed high conductivity of PVA/WO3/rGO/GCE. Under optimized conditions e.g. scan rate 80 mV/s, phosphate buffer (pH 6) as supporting electrolyte and potential window from -0.2 to 0.8 V, the prepared sensor showed excellent response for 4-AP. The linear dynamic range of developed method was optimized as 0.003-70 µM. The LOD of fabricated sensor based on PVA/WO3/rGO/GCE for 4-AP was calculated as 0.51 nM. The practical application of PVA/WO3/rGO/GCE was tested in real water and pharmaceutical samples. The fabricated sensor presented here, exhibited exceptional stability and sensitivity than the reported sensors and could be effectively used for the monitoring 4-AP without interferences.

Recent advances in carbon nanomaterials-based electrochemical sensors for food azo dyes detection.

Azo dyes as widely applied food colorants are popular for their stability and affordability. On the other hand, many of these dyes can have harmful impacts on living organs, which underscores the need to control the content of this group of dyes in food. Among the various analytical approaches for detecting the azo dyes, special attention has been paid to electro-analytical techniques for reasons such as admirable sensitivity, excellent selectivity, reproducibility, miniaturization, green nature, low cost, less time to prepare and detect of specimens and the ability to modify the electrode. Satisfactory results have been obtained so far for carbon-based nanomaterials in the fabrication of electrochemical sensing systems in detecting the levels of these materials in various specimens. The purpose of this review article is to investigate carbon nanomaterial-supported techniques for electrochemical sensing systems on the analysis of azo dyes in food samples in terms of carbon nanomaterials used, like carbon nanotubes (CNT) and graphene (Gr).

Magnetic nanoparticles based on cerium MOF supported on the MWCNT as a fluorescence quenching sensor for determination of 6-mercaptopurine.

In this study, a new magnetic nanocomposite was developed as an efficient and fast-response fluorescence quenching sensor for determination of anticancer drug 6-mercaptopurine (6-MP). For this purpose, the needle-shape fluorescence metal-organic framework of cerium (Ce-MOF) were successfully synthesized on the surface of multiwalled carbon nanotubes using 1,3,5-benzenetricarboxylic acid ligand via a facile solvothermal assisted route and magnetized. The accuracy of the proposed synthesis was confirmed using the FT-IR, FE-SEM, XRD, and VSM methods. The obtained product as presented the fluorescence emission in 331 nm by excitation of 293 nm in excitation/emission slit widths of 10.0 nm. The operation of suggested method is based on quenching the fluorescence signal in accordance with increasing the 6-MP concentration. The proposed assay effectively detected the trace amount of 6-MP in the linear range of 1.0 × 10-6 to 7 × 10-5 M. The limit of detection and limit of quantification were obtained as 8.6 × 10-7 and 2.86 × 10-6 M, respectively. The analyte molecule was determined in real samples with satisfactory recoveries between 98.75 and 105.33.

An improved electrochemical sensor based on triton X-100 functionalized SnO2 nanoparticles for ultrasensitive determination of cadmium.

The drastic increases in the concentration of heavy metals ions in the environment have become a serious concern for a number of years. Heavy metals pose serious impacts on human and aquatic life and cause severe health hazards. Amongst heavy metals, cadmium is known for its lethal effects on human health as it easily reacts with enzymes and creates free radicals in the biological system that causes carcinogenicity and other serious diseases. Thus, to tackle this challenge, TX-100 SnO2 nanoparticles based chemically modified sensor is introduced to assess the quantity of Cd+2 in the water system. The engineered SnO2 nanoparticles were electrochemically characterized through cyclic voltammetry and electrochemical impedance spectroscopy to ensure the better charge transfer kinetics and electrocatalytic properties of fabricated sensors. Under the optimized conditions e.g., scan rate 80 mV/s, PBS electrolyte pH 7, and potential window (-0.2 to -1.4 V), the engineered TX-100/SnO2/GCE-based sensor manifested a phenomenal response for cadmium ions in water media. The LOD and LOQ of developed TX-100/SnO2/GCE were calculated in the nanomolar range as 0.0084 nM and 0.27 nM. The recovery values of the proposed method for Cd+2 were found in an acceptable limit that witnesses the effectiveness of the fabricated sensor. Moreover, the excellent stability and anti-interference behavior of the sensor highlights its dynamic profile to be commercially utilized for the determination of Cd+2 ions in water bodies.

Determination of D&C Red 33 and Patent Blue V Azo dyes using an impressive electrochemical sensor based on carbon paste electrode modified with ZIF-8/g-C3N4/Co and ionic liquid in mouthwash and toothpaste as real samples.

Synthetic azo dyes are widely used in a variety of industries, but many of them pose a risk to human health, particularly when consumed in large quantities. As a result, their existence in products should be closely monitored. D&C red 33 and Patent Blue V are mostly used in cosmetics, especially in toothpaste and mouthwashes. A novel carbon paste electrode modified with ZIF-8/g-C3N4/Co nanocomposite and 1-methyl-3-butylimidazolium bromide as an ionic liquid was employed as a highly sensitive reproducible electrochemical sensor for the simultaneous determination of these common dyes. ZIF structure has unique properties such as high surface area, suitable conductivity, and excellent porosity. The electrochemical behavior of the suggested electrode was investigated by cyclic voltammetry (CV), differential pulse voltammetry (DPV), and electrochemical impedance spectroscopy (EIS). To characterize the synthesized nanocomposites, scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) were applied to investigate the structure of nanocomposites. Under the optimized conditions, the modified sensor offered a wide linear concentration range 0.08-10 µM (R2 = 0.9906) and 10-900 µM (R2 = 0.9932) with a low limit of detection of 0.034 µM. The value of diffusion coefficient (D), and the electron transfer coefficient (α) was calculated to be 310 × 10-5, and 0.9 respectively. This technique offered a successful performance for the determination of target analyte in the real samples with acceptable results between 96% and 107%.